This invention relates to machines for making non-woven bonded carpeting by forming a plurality of accordion-like chains of yarn between two backing layers and then severing the yarn between the layers to form two carpets and, more particularly, to the portion of such a machine that conveys the backing layers from their rolls to the point where the yarn is bonded to the backing layers.
Machines have been developed for making carpeting by folding a number of strands of yarn in a row simulataneously and planting them in a layer of adhesive spread across the surface of a sheet of backing material, and then repeating the operation on an opposing parallel sheet of backing material. This is done to form a series of accordion-type loops from each strand of yarn so that a plurality of lengths of material are bonded between the backing layers. After the adhesive has been cured, the loops are severed midway between the backing layers to form two separate carpets. Alternatively, individual lengths of yarn can be severed and one end planted in an adhesive coating on one backing layer and then another backing layer can be applied later to the other ends. Another type of machine has been developed in which the loops of yarn are formed initially without bonding them to the backing layers, and adhesive is applied later to the yarn.
In these types of operations, the adhesive can be used as the backing layer in addition to being the means for anchoring the yarn in place.
When a backing material is used, it is normally formed of woven strands of jute, although there are many other suitable types of backing material. The bonding material can be an adhesive such as a liquid synthetic resin which has been applied to the backing sheets or directly to the yarn. Ployvinylchloride (PVC) has been found to be effective.
In most machines, a roll of backing material is mounted on each side of the machine and the two webs of material are continuously advanced toward a well where they are disposed with one surface of each web parallel to a surface on the other web. Adhesive is applied to the layers as they are being advanced, the adhesive-coated surfaces facing each other in the well. At or near the top edge of the well a weaving mechanism such as the one shown and described in my copending U.S. application Ser. No. 323,440, filed Jan. 15, 1973, now U.S. Pat. No. 3,915,789, plants the yarn in the adhesive on one backing layer and then in the adhesive on the other backing layer to form what is known as yarn "sandwich." The sandwich passes through an oven to cure the adhesive and anchor the yarn to the backing layers. The yarn strands are then severed at some point between the backing layers to form two separate carpets. Any appropriate cutting mechanism can be used such as the ones shown and described in my copending U.S. application Ser. No. 315,845, filed Dec. 18, 1972, now abandoned and Ser. No. 425,890, filed Dec. 18, 1973, now U.S. Pat. No. 3,957,568 entitled "Cutter for Non-Woven Carpet Machine."
One problem in designing and building such machines is that oftentimes limited space conditions or the desire to eliminate expensive lifting mechanisms for the heavy rolls of backing material make it advantageous for the rolls to be mounted below the well, resulting in the material being conveyed upward from the roll. In prior art machines this is done by simply pulling the backing material from the roll toward the well. When a backing material such as jute is used this pulling upward requires a heavier grade material then is needed to form satisfactory carpeting so that the jute or other backing material is not torn or distorted by the pulling forces. A lighter grade of jute can be used for bonded carpeting than for example tufted carpeting because the adhesive used in bonded carpeting adds extra strength and durability to the backing layer. The lighter grade jute is advantageous because it significantly lowers the cost of the final product.
In addition, the alignment of the backing material in the direction of movement must be maintained as it moves toward the well. This must be done so that there is no lateral shifting which would result in a non-uniform final product and require an additional costly trimming step.